生物浮岛与漂浮植物对开放池塘水质净化效果

摘要

采用自主研发流量可控的密闭漂浮性水槽开展河道原位模拟实验,研究了挺水植物菖蒲(种植于浮岛上)与漂浮植物凤眼莲对受到城市污水污染的开放池塘水质净化效果以及系统中氮磷等污染物的归趋.结果表明,菖蒲和凤眼莲对水体藻类密度和叶绿素a削减率达到90％以上,对CODMn浓度削减率达到45％以上.经过10 m长水槽后,种植了凤眼莲的水槽水体其TN和TP浓度分别由3.71和0.24 mg/L降低至1.71和0.09 mg/L,而设置有菖蒲浮岛的水槽其水体TN和TP浓度则分别降低至2.69和0.16 mg/L.在水体N、P的总削减量中,凤眼莲吸收作用分别占84.31％和77.52％,而在菖蒲浮岛系统中,菖蒲的吸收作用仅分别占7.72％和8.55％,菖蒲净化系统中氮、磷的物理沉淀量显著高于凤眼莲组,分别达到35.26％和51.58％,但仍有57％和39％以上的氮和磷去向未知,推测可能与浮岛上生长的生物膜有关.研究结果可为选用凤眼莲和浮岛植物修复技术进行污染水体生态修复理论研究与实践运用提供借签和参考.%The self-developed experimental device ofa cuboid sink welded with stainless steel (10.0 m × 1.0 m ×0.5 m) without the top cover was used to investigate water purification of open pond contaminated with domestic sewage using biological floating island growing with Acorus calamus L.and Eichhornia crassipes,and the fates of nitrogen (N) and phosphorus (P) in the water purification system.The results revealed that the removal rates of algal density and chlorophyll a were over 90％,and the removal rate of CODMn concentration was over 45％.Total nitrogen (TN) and total phosphorus (TP) concentrations of the polluted water by running through the 10 m sinks decreased from 3.71 and 0.24 mg/L to 1.71 and 0.09 mg/L by E.crassipes,and to 2.69 and 0.16 mg/L by A.calamus,respectively.The main fate for N and P in the purification system with E.crassipes was absorbed by the plants,which accounted for 84.31％ and 77.52％ decrease of the TN and TP,respectively;while the N and P absorbed by plants in the system with A.calamus only accounted for 7.72％ and 8.55％ reduction,respectively.A large proportion TN (35.26％) and TP (51.58％) existed in the sediments in the sinks with A.calamus,while location of over 57％ and 39％ of the TN and TP were unclear in the system,which may relate to the biofilm growing on the floating island.This study provides practical and theoretical references for ecological restoration of open pond contaminated with domestic sewage using phytoremediation technology with floating island and E.crassipes.